Stack of bags

ABSTRACT

A stack ( 2 ) of individual, pre-formed bags, each bag ( 4 ) comprising: a body portion ( 6 ) formed by front ( 8 ) and rear ( 10 ) walls having closed sides ( 12 ), a closed bottom ( 13 ) and an open mouth ( 14 ); first and second side handles ( 16, 18 ) extending away from the body portion ( 6 ) at opposite sides of the open mouth ( 14 ); and a block header ( 20 ) separably connected to the first and second side handles ( 16, 18 ), wherein the block header ( 20 ) is provided with at least one internal line of weakness ( 26, 28 ) such that it may be divided into individual attachment tabs ( 40, 41, 42 ), each attachment tab being provided with a support member receiving aperture ( 43, 44, 45 ) for receiving a support member of a bag dispenser.

The present invention relates to a stack of bags.

It is common practice for supermarkets and other retail outlets to provide plastic bags at the checkout, or other suitable location, into which customers may pack their shopping. The most common type of bag is the so-called T-shirt type bag which comprises a bag portion, formed by front and rear walls having a closed sides, a closed bottom and an open mouth, and two looped side handles extending therefrom. Typically the bags are provided in the form of a stack of bags. The bags in the stack may be connected by a variety of means, for example, heat bonding or other suitable means.

Stacks of bags are well known in which the handle portions of each bag are bridged by bridging webs of plastic connected to the handle portions at each end by lines of weakness (e.g. defined by perforations). The bridging webs are held together (e.g. by heat bonding, taping, wrapping, clipping and/or tying) to form a so-called block header between the handle portions of the stack. This provides a large through-channel in the stack in the region of the mouth of the bags. GB 2 329 629 discloses a stack of bags of the type described, in which the block header is also attached to the stack of bags at the mouth of the bags. Stacks of bags of this kind maybe mounted on dispensers having retaining members arranged to extend through the channel defined by the block headers, handles and mouths of the bags and retain the bags in position for dispensing. The retaining members may wrap around the block header for increased stability.

Another well known stack of bags is disclosed in U.S. Pat. No. Re. 33,264. This stack of bags comprises aligned mounting apertures through the handles of the bags and a central, separable mounting tab provided at the mouth of the bags. Such a stack of bags may conveniently be mounted on a dispenser having a pair of spaced apart supporting arms arranged to engage with the mounting apertures provided in the handles. The dispenser further comprises a transverse member extending between the support arms and itself supporting a hook element arranged to engage with the central, separable mounting tab.

A variety of different bag dispensers are known all of which set out to achieve two main objectives: to dispense individual bags one at a time and to dispense the bag to the customer in a partially open condition.

In order to dispense the bags in a partially open condition it has become common to provide a region of adhesion between adjacent bags in the stack. The region of adhesion may suitably be in the form of a “glue spot” provided near the mouth of adjacent bags. U.S. Pat. No. 5,421,803 discloses the use of such glue spots. As the first bag in the stack is removed from the dispenser by the customer the front wall of the next bag in the stack is pulled forward. The glues used are typically contact adhesives or hot melt adhesives and are selected to have a breaking point in the region of about 4 to 9 Newtons. It is intended that the connection between the first bag in the stack and the next bag will be broken as the first bag is pulled away, leaving the next bag partially open and ready to use. However, it has been found that when the first bag on the stack is removed, not merely the next bag but the next three or four bags are pulled forward and opened to some extent. This effect is known as “daisychaining” and is an undesirable consequence of providing regions of adhesion.

An alternative to the use of “glue spots” is disclosed in U.S. Pat. No. 5,087,234. It has been shown that adjacent bags in a stack can be caused to adhere to one another in the mouth region by a combination of corona discharge treatment and pressure. As disclosed in U.S. Pat. No. 5,087,234 the mechanism for this adhesion is not fully understood. However, it has been shown that the combination of the corona discharge treatment and the pressure applied during the formation of the handles, bag mouth and centre tab result in the formation of an area of adhesion between the outer surfaces of adjacent bags.

Conventionally, corona discharge treatment has been used to treat the surface of polyethylene bags to make them receptive to ink. This procedure is done in order to apply logos and the like to the bags. In its natural state, polyethylene has a surface energy of approximately 30 dynes/cm. In order to make it receptive to ink the surface energy must be raised to about 38 dynes/cm. This is known as increasing the “wettability” of the polyethylene and this can be done using corona discharge treatment. Treating the bags to a level greater than 38 dynes/cm combined with the pressure applied in forming the bag mouth results in an area of adhesion being formed between adjacent bags.

The bags disclosed in U.S. Pat. No. 5,087,234 overcome some, but not all, of the problems of the “glue spot” bags. For example, customers are still likely to grasp the bag at the bottom. This problem can be overcome by using a dispenser as disclosed in UK Patent Application No. 0302334.8. This application, in the name of the present applicant, discloses a dispenser comprising a base, a body part extending from the base, a stack support member attached to the body part and stack retention means attached to the stack support member. The stack support member comprises a planar region inclined upwards from back to front with respect to the base and an arcuate lip provided at the front of the planar region, wherein the arrangement is such that, in use, the stack of bags are engaged by the stack retention means in such a manner that the handles of the bags are supported by the planar region of the stack support means and a portion of the bags in the region of the mouth of the bags is disposed on the arcuate lip with the body of the bags depending therefrom, such that a first bag of the stack may conveniently be grasped by a user to remove a single bag in a partially open condition from the stack.

According to the present invention, there is provided a stack of individual, pre-formed bags, each bag comprising: a body portion formed by front and rear walls having closed sides, a closed bottom and an open mouth; first and second side handles extending away from the body portion at opposite sides of the open mouth; and a block header separably connected to the first and second side handles, wherein the block header is provided with at least one internal line of weakness such that it may be divided into individual attachment tabs, each attachment tab being provided with a support member receiving aperture for receiving a support member of a bag dispenser.

Preferably, the block header is attached to the body portion of the bags at the mouth of the bags.

When the block header is attached to the body portion of the bags at the mouth it is preferred that the block header is provided with two internal lines of weakness such that it may be divided into three individual attachment tabs, first and second attachment tabs being attached to the first and second handles respectively and a third attachment tab being attached to he body portion at the mouth of the bag.

The stack of bags may be easily adapted to be used on more than one type of dispenser. The provision of such a “universal” stack of bags greatly reduces manufacturing costs since a single stack of bags can be produced for all retail outlets and this can then be adapted at the point of sale to fit a particular bag dispenser.

The stack of bags is provided to the customer, which will normally be a retail outlet, in a first state. In the first state the block header is intact and separably connected to the first and second side handles and, if applicable, to the body portion at the mouth. In this state the stack of bags may be mounted of a dispenser having retaining members which extend through the channels defined by the block header, handles and mouth of the bag. The support member receiving apertures are not normally used to support the stack when it is in the first state.

If the bag dispenser is of the type commonly referred to as rack arms, in which a pair of spaced apart support members are provided with a hook element therebetween, then a stack of bags in the first state would not be suitable for engagement with such a dispenser. Traditionally this has meant that different stacks of bags have been required for each type of dispenser.

However, a stack of bags according to the present invention may be easily adapted to be used with such a dispenser. The block header may be separated along its internal line(s) of weakness to provide at least two individual attachment tabs separably connected to the handles. In the case where the block header is attached to the mouth of the bag it may be separated along its two lines of weakness in order provide three individual attachment tabs, first and second attachment tabs separably connected to the side handles and a further attachment tab separably connected to the body portion at the mouth of the bag. In the case where the block header is only attached to the side handles it is preferred that a further attachment tab is provided at the mouth of the bag. The attachment tabs have support member receiving apertures through which the spaced apart support members and the hook element may extend.

Preferably, the block header comprises a first portion in the form of a bridging web which extends between the first and second side handles, and a second portion extending downwardly from the mid-point of the bridging web and being attached to the body portion at the mouth of the bag. This form of block header may be generally though of as a “T-bar”, in which the cross bar of the “T” extends between the first and second handles and the stem of the “T” is attached to the mouth of the bag.

Alternatively, the block header may simply be in the form of a bridging web of material extending between the first and second side handles, with a projection extending upwardly from the mouth of the bags and being attached to the bridging web.

As a further alternative, the block header may be in the form of a “T” bar and the bag may comprise a projection extending upwardly form the mouth of the bag and attached to the stem of the “T”.

It is preferred that a portion of the rear wall of one bag in the stack is attached to a portion of the front wall of the next bag in the stack.

The attachment may conveniently be effected by means of an adhesive. The adhesive may be a contact adhesive or a hot melt adhesive and is typically provided in the centre of the bag adjacent the mouth. The breaking point of the attachment is preferably in the region of about 4 to 9 Newtons. As the top bag of the stack is removed from the dispenser the region of adhesion between the rear wall of the top bag and the front wall of the next bag causes the front wall of the next bag to be pulled forward. The adhesion is relatively weak and will break as the top bag is pulled away, leaving the next bag partially open and ready for the next consumer to use.

Alternatively, the attachment may be effected by means of corona discharge treatment during the formation of the stack of bags. Corona discharge treatment in combination with pressure exerted in cutting the mouth ends of the bags causes the rear wall of the top bag in the stack to adhere to the front wall of the next bag in the stack. This has a similar practical effect as the provision of a glue spot.

For a better understanding of the present invention reference will now be made to the accompanying drawings showing, solely by way of example, an embodiment of the present invention and, in which:

FIG. 1 shows a plan view of a stack of bags in a first state;

FIG. 2 shows a plan view of a close up of the handle end of a stack of bags in a second state with the block header separated along both of its internal lines of weakness;

FIG. 3 shows a front perspective view of a stack of bags as shown in FIG. 1 mounted on a dispenser;

FIG. 4 shows a top perspective view of the dispenser and bags of FIG. 3;

FIG. 5 shows a first perspective view of a stack of bags as shown in FIG. 2 mounted on a dispenser; and

FIG. 6 shows a second perspective view of a stack of bags as shown in FIG. 2 mounted on a dispenser.

Referring firstly to FIG. 1, this shows a plan view of a stack of bags 2. Each bag 4 comprises a bag portion 6 formed by front 8 and rear 10 walls having closed sides 12, a closed bottom 13 and an open mouth 14. First and second looped side handles 16, 18 are provided extending upwardly away from the bag portion 6 at opposite sides of the mouth 14.

The handles 16, 18 are bridged by a bridging web of a block header 20 which extends between the handles and is separably attached thereto along lines of weakness 17, 19. The bags 4 are held together in the stack by hot pin welds 15 in the block header 20.

Tabs 22, 23 extend upwardly from the front 8 and rear 10 walls respectively. The tabs 22,23 extend from the mouth 14 of the bag portion 6, mid-way between the side handles 16, 18, and are separably connected to the block header 20 along a line of weakness 24. The lines of weakness 17, 19, 24 are formed by cuts in the bag material which weaken the attachment between the bag 4 and the block header 20. Alternatively, the lines of weakness 17, 19, 24 may be formed by perforations, discontinuations or any other suitable feature.

The block header 20 is provided with further internal lines of weakness 26, 28. Again, the lines of weakness 26, 28 are formed by cuts in the bag material. Internal lines of weakness 26, 28 divide the block header 20 into three distinct portions (as shown more clearly in FIG. 2).

The stack of bags 2 of the present invention are suitably manufactured in generally conventional manner. A thermoplastic tube, for example of a polyethylene or other polyester film, is collapsed, sealed, corona discharge treated and severed transversely at intervals along its length, along lines which ultimately constitute the mouth 14 end and the sealed bottom 13 of the bags 2. Thereafter, a plurality of these end sealed bag forming portions are stacked one upon the other and a suitably designed cutting die cuts through the stack simultaneously forming the handles 16, 18, block header 20 and mouth 14. The lines of weakness 17, 19, 24,26 and 28 may be formed simultaneously with this cutting or during a subsequent step. A hot pin welding or other pin perforation of the bags can also be provided, advantageously in the block header 20 to retain the bags in their stacked configuration.

The combination of the corona discharge treatment and the pressure applied by the cutting die causes adjacent bags in the stack to adhere to one another in the region of the cuts. Alternatively, a glue spot may be applied to the individual bag forming portions prior to stacking and cutting.

The stack of bags 2 as shown in FIG. 1 represents the first state of the stack 2. This is the normal state in which the stack 2 will be supplied to the customer. In this state the stack 2 may be mounted on a bag dispenser 30 as shown in FIGS. 3 and 4. The dispenser 30 comprises a base (not shown) which may be fixed at a suitable location, for example, at a supermarket checkout. A body part (not shown) extends vertically upwards from the base and has a stack support member 34 at its top end. The stack support member 34 comprises a planar region 35 inclined upwards from back to front with respect to the base and an arcuate lip 36 provided at the front of the planar region 35. Stack retaining members 38 are provided on the stack support member 34. The stack retaining members are provided towards the rear of the stack support member 34 and are in the form of prongs which extend through the channels defined by the handles 16, 18, the block header 20, the tabs 22, 23 and the mouths 14 of the bags. The stack retaining members 38 are angled towards the rear of the stack support member 34.

In use, the stack of bags 2 is mounted on the dispenser 30 by engagement of the stack retaining members 38 with the channels defined by the handles 16, 18, the block header 20, the tabs 22, 23 and the mouths 14 of the bags. The handles 16, 18 are supported by the planar region 35 of the stack support member 34 and the mouths 14 are disposed on the arcuate lip 36 with the bag portion 6 depending therefrom.

A portion of the rear wall 10 of each bag 4 in the stack 2 is separably attached to a portion of the front wall 8 of the next bag in the stack 2. This is effected by means of the combination of the corona discharge treatment and the pressure of the cutter during the formation of the stack of bags 2. As the top bag in the stack 2 is removed from the dispenser 30 the last point of attachment between the rear wall 10 of the top bag and the front wall 8 of the next bag will be at the tabs 22, 23. As the top bag is removed this causes tab 22 on the front wall 8 of the next bag in the stack 2 to be drawn forward, thus partially opening the mouth 14 of the next bag 3. When the attachment breaks the next bag becomes the top bag of the stack and the tab 22 on the front wall hangs forward and provides a point at which the customer may grasp the bag. The attachment between the bags is relatively weak and breaks as the first bag is fully removed from the dispenser, leaving the next bag in a partially open configuration.

FIG. 4 shows a top perspective view of the stack of bags 2 and dispenser 30 of FIG. 3. The engagement between the stack retaining members 38 and the stack 2 can be clearly seen.

FIG. 2 shows a plan view of a close up of the handle end of a stack of bags 2 in a second state. A stack of bags 2 as shown in FIG. 1 can be quickly and easily converted into a stack of bags 2 as shown in FIG. 2. The internal lines of weakness 26, 28 in the block header 20 have been broken to provide three individual attachment tabs 40, 41, 42. First and second attachment tabs 40, 42 are provided on first and second side handles 16, 18 respectively and the third attachment tab 41 is attached to the tabs 22, 23 at the mouth 14 of the bag 4.

The attachment tabs 40,41,42 are all provided with support member receiving apertures 43,44,45 respectively for receiving a corresponding support member of a bag dispenser. The support member receiving apertures 43, 44, 45 are formed by using a suitable cutting dye. A portion of the perimeter of the apertures 43, 44, 45 is left uncut such that flaps of bag material remain which are attached to the attachment tabs 40, 41, 42 at a minor region. The support member receiving apertures 43, 44, 45 are provided in the block header 20 when the stack of bags 2 are in the first state but are only normally used to support the stack 2 on a dispenser when the stack 2 is in the second state. The stack of bags 2 can easily be converted from the first state to the second state by breaking the internal lines of weakness 26, 28. The internal lines of weakness are significantly weaker than the lines of weakness between the block header 20 and the side handles 16, 18.

Referring now to FIGS. 5 and 6, these show a stack of bags 2 in a second state as shown in FIG. 2, mounted on a dispenser 50. The dispenser 50 comprises a base 52 which may be fixed at a suitable location, for example, at a supermarket checkout. A body member extends vertically upwards from the base and supports a pair of spaced apart supporting arms 54, 56 which are generally parallel to the base 52 and are spaced apart by a distance approximately equal to the width of the bags 2. The dispenser 50 further comprises a transverse member 58 extending between the supporting arms 54, 56 and itself supporting a hook member 60, disposed mid-way between the supporting arms 54, 56. In use, the stack of bags 2 is mounted on the dispenser 50 by engagement of the supporting arms 54, 56 with the support member receiving apertures 43, 45, provided on the first and second attachment tabs 40,42. The supporting arms 54,56 pass through the support member receiving apertures 40,42 and the bag portion 6 depends therefrom. The third attachment tab 41 is engaged by the hook member 60.

The stack of bags 2 are loaded onto the dispenser 50 in the conventional manner, by first engaging the supporting arms 54, 56 with the support member receiving apertures 43, 45 and then sliding the stack of bags 2 onto the dispenser 50. The hook member 60 is then engaged with the support member receiving aperture 44 on the third attachment tab 41. The loading action is preferably undertaken by a member of staff. The member of staff should then remove the top bag of the stack prior to use of the dispenser 50 by a customer. Removal of the first bag of the stack 2 causes the mouth of the next bag in the stack to be partially opened as shown in FIG. 6. This improves access to the bag and enables a customer to load their shopping easily.

With the stack loaded on to the dispenser as described, the tab 22 on the front wall 8 of the first bag in the stack hangs forward and provides a point at which the customer can grasp the bag. In order to remove the first bag from the stack the customer grasps the tab 22 and pulls in a direction away from the dispenser 50. Since the support member receiving apertures 43,45 are engaged by the supporting arms 54, 56 the customer must pull the bag in a direction generally parallel to the supporting arms.

As the first bag is removed by the customer it first breaks contact with attachment tabs 40, 42 along lines of weakness 17, 19. Next, the bag breaks contact with the central attachment tab 41 along line of weakness 24. At this point the only remaining point of attachment between the first bag in the stack and the other bags in the stack is between the tab 23 on the rear wall 10 of the first bag and the tab 22 on the front wall 8 of the second bag. This attachment is effected by means of the combination of the corona discharge treatment and the pressure of the cutter which forms the mouth area of the bags and is relatively weak. As the first bag is fully removed from the dispenser 50 the tab 22 on the front wall 8 of the second bag in the stack is pulled forward such that the second bag is partially opened, as shown in FIG. 6. The second bag in the stack now becomes the first bag and the tab 22 hangs forward, ready to be grasped by the next customer. 

1. A stack of individual, pre-formed bags, each bag comprising: a body portion formed by front and rear walls having closed sides, a closed bottom and an open mouth; first and second side handles extending away from the body portion at opposite sides of the open mouth; and a block header separably connected to the first and second side handles, wherein the block header is provided with at least one internal line of weakness such that it may be divided into individual attachment tabs, each attachment tab being provided with a support member receiving aperture for receiving a support member of a bag dispenser.
 2. A stack of individual, pre-formed bags according to claim 1, wherein the block header is attached to the body portion of the bags at the mouth of the bags.
 3. A stack of individual, preformed bags according to claim 2, wherein the block header is provided with two internal lines of weakness such that it may be divided into three individual attachment tabs, first and second attachment tabs being attached to the first and second handles respectively and a third attachment tab being attached to he body portion at the mouth of the bag.
 4. A stack of individual, pre-formed bags according to claim 2, wherein the block header comprises a first portion in the form of a bridging web extending between the first and second side handles and a second portion extending downwardly from the mid-point of the bridging web and attached to the body portion at the mouth of the bag.
 5. A stack of individual, pre-formed bags according to claim 2, wherein the block header is in the form of a bridging web extending between the first and second side handles and the body portion of the bag comprises a projection extending upwardly from the mouth and attached to the bridging web.
 6. A stack of individual, pre-formed bags according to claim 1, wherein a portion of the rear wall of one bag in the stack is attached to a portion of the front wall of the next bag in the stack.
 7. A stack of individual, pre-formed bags according to claim 6, wherein the attachment is effected by means of an adhesive.
 8. A stack of individual, pre-formed bags according to claim 6, wherein the attachment is effected by means of corona discharge treatment during the formation of the stack of bags. 